The Gordon Research Conferences bring together the most active workers in a given area of research for the purpose of in-depth communication, exchange of information and technologies, and discussion of ideas that will stimulate and strengthen the world- wide research efforts in that field. The 1987 Conference on Hormone Action represents the 17th Conference in a series which began in 1969. This conference promotes the exchange of information about the rapidly expanding field of the molecular mechanisms involved in hormone action. This year's Conference will cover a broad range of topics dealing with the structure and function of hormone receptors, regulatory mechanisms of gene expression, hormonal control of reproductive function, hormones and cancer intracellular mediators of hormone action, calcium channels and bone growth, peptide hormone genes and action and thyroid regulation of cellular metabolism. In contract to most other meetings, this Conference brings together a diverse group of scientists studying a spectrum of organisms from bacterial systems to man, and whose interests include hormones whose action is primarily intracellular (steroid and thyroid hormones) and hormones whose initial action is at the membrane (peptide hormones). The participants range from basic scientists studying the most fundamental aspects of cellular regulation to physician- scientists interested in applications of these techniques to human disease. The workshop nature of the conference, with open posters sessions and a limited attendance policy, promotes a broad participation from all conferees.